Recently, with the improvement of the standard of living of people, a large number of household appliances enter people's life. Meanwhile, with the rapid development of the mobile network, more and more people possess mobile phones. Thus, there arises a demand of controlling the household appliance using the mobile phone, and meanwhile it is required that the manner for remote interaction be simple, convenient and reliable.
The traditional system for remote household appliance control is mainly implemented by means of short message, but it has the following problems:
1) the security is poor;
2) the real-time performance is poor. The short message is transmitted in the store-and-forward manner, so the short message may be caused to fail to reach the destination household appliance in time due to reasons such as network congestion;
3) devices like GSM (Global System for Mobile Communications) MODEM need to be configured to perform control using the short message, so the costs are high;
4) the interaction is poor, and the user's experience is not friendly enough.
The Unstructured Supplementary Service Data (USSD) service is a novel interaction session data service that is real-time online and based on the global mobile communication network. This service is currently mature in technology, the data are transmitted using the signaling channel of the network based on the SIM (Subscriber Identity Module) card, and it is connection-oriented, so the reliability is high.
Both USSD and Short Messaging Service (SMS) are transmitted through the signaling channel of the network. The difference is that the short message adopts the store-and-forward manner, while USSD adopts the session-oriented manner. When a user visits a USSD service, the session path keeps connected until the session is over. In addition, since a transmission USSD string transparent path directly reaching an external service node through the HLR (Home Location Register) is provided, the user can also visit the service node outside the GSM network.
In a word, the USSD has the following features:
(1) Rapid. In the interactive application, since it only needs to establish the connection once, the delay for establishing the signaling connection for multiple times is reduced, the response time for one round is shorter than that of short message, and can be one seventh of the corresponding time for short message at most.
(2) Convenient. The user does not need to perform stepped menu selection, but directly enters the USSD command string.
(3) Support roaming. Each command of USSD passes through the HLR, so it operates in the same way as based on the USSD service when the user is roaming.
(4) Wide applicability. The USSD can be operated on all current mobile phones.
(5) Strong functions. Services can be provided in the session manner and information service menu manner.
3GPP (Third Generation Partnership Project) also includes the description on USSD, and both WCDMA (Wideband Code Division Multiple Access) and TD-SCDMA (Time Division-Synchronous Code Division Multiple Access) comply with the 3GPP standards, that is, the USSD technology can be widely supported in GSM, WCDMA and TD-SCDMA networks.
Infrared remote control is a remote control means that is used most widely at present, and this technology transmits a remote control instruction using near-infrared light with a wavelength of 0.76 um-1.5 um, and has a high transmission efficiency and high reliability.